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Date:   Sun, 25 Aug 2019 00:37:54 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Ralph Campbell <rcampbell@nvidia.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        nouveau@lists.freedesktop.org,
        =?iso-8859-1?B?Suly9G1l?= Glisse <jglisse@redhat.com>,
        Jason Gunthorpe <jgg@mellanox.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 1/2] mm/hmm: hmm_range_fault() NULL pointer bug
Message-ID: <20190824223754.GA21891@lst.de>
References: <20190823221753.2514-1-rcampbell@nvidia.com> <20190823221753.2514-2-rcampbell@nvidia.com>
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On Fri, Aug 23, 2019 at 03:17:52PM -0700, Ralph Campbell wrote:
> Although hmm_range_fault() calls find_vma() to make sure that a vma exists
> before calling walk_page_range(), hmm_vma_walk_hole() can still be called
> with walk->vma == NULL if the start and end address are not contained
> within the vma range.

Should we convert to walk_vma_range instead?  Or keep walk_page_range
but drop searching the vma ourselves?

Except for that the patch looks good to me:

Reviewed-by: Christoph Hellwig <hch@lst.de>